Geography Project


Volcanoes are mostly unpredictable. But, there are some means of detection and prediction, both natural and scientific.
Close observance of the area around a volcano can provide important signals. Clouds of steam or smoke may arise from the volcano’s crater. The ground may rumble. There may be minor shudders or earthquakes.
The increased temperature of nearby streams, springs, and even surface rocks may give a clue. Rock slides or avalanches from the volcano’s cone or slopes provide evidence of possible eruption. However, all these things may happen without further volcanic activity. These are the natural means of detection of eruption.
Scientists have developed various instruments to measure predictors of volcanic eruption. The ground may tilt slightly before an eruption; a tilt meter measures this activity. Seismographs, commonly used in recording earthquakes, can also be used to gauge the rumblings that sometimes come before an eruption.
Rising magma distorts Earth’s natural electric currents and magnetic field. A restivity meter and a magnetometer note these changes. Thermometers register changing temperatures in the surrounding environment, which may precede volcanic eruptions. These are the scientific means of detection of eruption.
Despite all of these ways to monitor volcanoes, eruptions and explosions are difficult to predict. For example, in 1980, scientists thought that Mount Saint Helens—a dormant volcano in Washington State—was preparing for a mild eruption.
They were taken by surprise. On the morning of May 18, the volcano blew its top, spewing clouds, lava, ash, and rocks; causing avalanches, mudslides, and floods; and registering moderate earthquakes between 3 and 5 on the Richter scale.
The Richter scale measures the magnitude of earthquakes on a scale of 0 to 9.0. More than 60 people died and about 200 were left homeless. The damage and destruction covered more than 200 square miles (518 square kilometers).
Instruments that are used to predict volcanoe eruptions
A seismometer (or seismograph) is a sensor that detects the intensity of earthquakes caused by magma that is moving. It has been around for almost 2,000 years. The first seismograph was invented by a Chinese scientist. It looked like a large jar with dragon heads on every side. Each dragon had a metal ball in its mouth, and when an earthquake struck, one of the balls would drop into the open mouth of a toad sculpture below. By looking at which ball dropped, Heng (the inventor) said he could tell from which direction the earthquake came. (Actually he couldn't but it was a good guess!)
Luigi Palmieri invented a seismograph in 1856 while working near Italy's Mt. Vesuvias. He wanted a way to predict eruptions, and knew that tremors were usually felt before an eruption. The seismograph uses a pendulum to record movement of the ground below it. The squiggly lines recorded on paper by a seismograph are called a seismogram.
-- Since magma gives off electric currents, electric meters are used tospot rising magma levels by measuring its electric current. Gravimeters can also detect flowing magma.
-- Scientists also take temperatures and gauge gas by using a Landsat satellite. The satellite uses infared sensors to detect temperatures and changes in volcanoes. Aircraft monitors the amount of gas released from the ground. An increase in sulfur dioxide and other gases usually means that there could be volcanic eruptions.
-- The tiltmeter is a sensor that uses a laser beam to find the rising or lowering of magma levels by measuring changes in ground elevation.
-- GPS(Global Positioning System) is a method to determine position of locations on Earth. It uses satellites that broadcast a signal and receivers that pick up and record the signal. GPS uses the relationship between velocity, distance, and time (velocity equals distance divided by time). With GPS, the velocity is the speed of light. Knowing the velocity and time (and the position of the satellite) allows the distance to be calculated. As magma moves up into a volcano the volcano swells and distances between points on the volcano increases (think of dots on a balloon) and the elevation at specific points increases. Such a change is a common occurrence prior to an eruption.
Volcanologists use these instruments to successfully predict eruptions which saves many lives. Scientists are trying to develop new ways to predict future eruptions.


Why do so many people still live near volcanoes?
This is because to them, the advantage of living near a volcano beats the disadvantages. These are some factors of why people live near volcanoes:
Minerals
Magma contains a variety of minerals. When it rises from the Earth's core and cools, minerals are precipitated out due to processes like the movement of superheated water and gasses through the rock. The type of mineral that precipitates out differs in different locations. This shows that it is possible minerals like tin to rare minerals like diamonds in volcanic rocks! Frequently, metallic minerals like copper or gold are found in rocks deep below extinct volcanoes, making it possible for large scale commercial mining and smaller scale local activities by people going alone and in small groups of local. The mineralizations of both active and dormant volcanoes are the same so both types are rich sources of minerals. Also, when hot gasses escape, they bring minerals to the surface, usually sulfur, the mineral collects around the vents as it condenses and solidifies. Locals collect the mineral and sell it.
Geothermal Energy
The definition of Geothermal Energy is heat energy from the Earth. It is unwise to use the heat directly, e.g. building your house on top of a steam vent because it will be unpredictable, dangerous and messy. Using the heat from underground steam, turbines can be turned to produce electricity or to provide household heating and hot water. If it is impossible to use the steam naturally, deep holes are drilled into very hot rocks, cool water is pumped down and steam is extracted from another nearby hole. Due to the fact that the steam contains too many dissolved minerals that may precipitate out and clog pipes, corrode metal components and possibly poison water supply, the steam won't be used directly. Countries like Iceland use a lot of geothermal power, approximately two third of Iceland's electricity comes from steam powered turbines. New Zealand and even Japan though at a lesser extent, make use of geothermal energy effectively too.
Fertile Soils
As volcanic rocks are rich in minerals, they form some of the world's richest soils. However, the rocks require a few millenniums of weathering to be broken down into rich soils. Places like the African Rift Valley, Mt Elgon in Uganda and the slopes of Mount Vesuvius in Italy all have productive soils because of that. Due to the 2 major eruptions 35,000 and 12,000 years ago, the Naples area, including Mount Vesuvius have very rich soils because of the weathered ash and rocks left after the eruptions. The land there is not wasted today and is used to cultivate fruits and plants like grapes, orange, lemon trees, herbs and even flowers. It has also become a large tomato growing area.
Tourism
There are many reasons why volcanoes attract millions of tourists every year, some tourists like to see volcanic eruptions, some like to see the volcano puff out steam, smoke and hot ash. These amaze and therefore attract the tourists. Some other tourists also like the warm bathing lakes, hot springs, bubbling mud pools, steam vents and even geysers near volcanoes. Old Faithful is such a popular tourist area that it even has its 24/7 Old Faithful webcam. Old Faithful is located in the Yellowstone National Park of USA. Countries like Iceland are able to attract many tourists as there are volcanoes and glaciers which are often seen together. Tourists are also able to see what Earth might have looked like a long time ago. Tourism boosts the economy of the country as it provides business for restaurants, hotels, etc. Other countries like Uganda are also trying to benefit from tourism by working hard to improve its volcanic region.


Why is the impact of the 1815 eruption still being felt today?


In Sumbawa, Indonesia, a volcano erupted in 1815 which rained ash so far until that even Java was affected. The eruption created global climate anomalies that included the phenomenon known as volcanic winter. The effect on North America and Europe was so bad that they experienced a year without summer. Agricultural crops failed and livestock died in much of the Northern Hemisphere, resulting in the worst famine of the 19th century. The aftermath triggered a tsunami in Sanggar at night. Not only it triggered a tsunami but the eruption also cause abnormal weather and wind speeds and the atmosphere under went a change for at least a month.

The 1815 eruption released sulfur into the stratosphere, causing a global climate anomaly. Different methods have estimated the ejected sulfur mass during the eruption: the petrological method; an optical depth measurement based on anatomical observations; and the polar ice core sulfate concentration method, using cores from Greenland and Antarctica.
In the spring and summer of 1815, a persistent dry fog was observed in the northeastern United States. The fog reddened and dimmed the sunlight, such that sunspots were visible to the naked eye. Neither wind nor rainfall dispersed the "fog". It was identified as a stratospheric sulfate aerosol veil. In summer 1816, countries in the Northern Hemisphere suffered extreme weather conditions, dubbed the Year Without a Summer. Average global temperatures decreased about 0.4–0.7 °C enough to cause significant agricultural problems around the globe. On 4 June 1816, frosts were reported in Connecticut, and by the following day, most of New England was gripped by the cold front. On 6 June 1816, snow fell in Albany, New York, and Dennysville, Maine. Such conditions occurred for at least three months and ruined most agricultural crops in North America. Canada experienced extreme cold during that summer. Snow 30 cm (12 in) deep accumulated near Quebec City from 6 to 10 June 1816.
1816 was the second coldest year in the northern hemisphere since CE 1400, after 1601 following the 1600 Huaynaputina eruption in Peru. The 1810s are the coldest decade on record, a result of Tambora's 1815 eruption and other suspected eruptions somewhere between 1809 and 1810 (see sulfate concentration figure from ice core data). The surface temperature anomalies during the summer of 1816, 1817 and 1818 were −0.51, −0.44 and −0.29 °C, respectively. As well as a cooler summer, parts of Europe experienced a stormier winter.
This pattern of climate anomaly has been blamed for the severity of typhus epidemic in southeast Europe and the eastern Mediterranean between 1816 and 1819. Much livestock died in New England during the winter of 1816–1817. Cool temperatures and heavy rains resulted in failed harvests in the United Kingdom of Great Britain and Ireland. Families in Wales traveled long distances as refugees, begging for food. Famine was prevalent in north and southwest Ireland, following the failure of wheat, oat and potato harvests. The crisis was severe in Germany, where food prices rose sharply. Due to the unknown cause of the problems, demonstrations in front of grain markets and bakeries, followed by riots, arson and looting, took place in many European cities. It was the worst famine of the 19th century.


Ideas of reducing negative impact of living near volanco
1)Build walls in the way to divert the lava in case of eruption of lava .
2) Dig trenches away from nearby towns/villages to divert the flow of lava in case of eruption .
3)Have an evacuation plan to evacuate properly and fast during eruption of lava .

Credits
http://www.geography-site.co.uk/pages/physical/earth/volcanoes/volcanoliving.html
http://wiki.answers.com/Q/What_can_be_done_to_reduce_the_impact_of_a_volcano



Done By: Ervins Ong (21) , Ryan Tan (34) , Weichong (38) , Joseph Lye (26) .